Crankcase ventilation



Oct. 1, 1957 R. A. WITTREN 2,808,040

CRANKCASE VENTILATION Filed May 9, 1955 FlG.l

FIG.2

. INVENTOR." R. A. wnmsn 2,808,040 Cg Patented on. 1, 1957 CRANKCASE VENTILATION Richard A. Wittren, Cedar Falls, Iowa, assignor to Deere llvlanufacturing Co., Dubuque, Iowa, a corporation of owa Application May 9, 1955, Serial No. 506,936

3 Claims. (Cl. 123-41.86)

This invention relates to crankcase ventilation for internal combustion engines and more particularly to an improvement in such system by the use therein of a pump or impeller of the liquid-packing-ring type.

The nature and advantages of crankcase ventilation are so well known in the art as to require no elaboration here. In the ordinary case, clean air is taken into a pump or other pressure-modifying means for transfer to the crankcase, the air passing through the crankcase and exiting through an air outlet to carry off from the crankcase undesirable vapors and other impurities. In the case of the conventional automobile, normal road speeds are sufliciently high to permit ventilation of the crankcase without the use of a special pump, but in the cases of agricultural tractors, which operate at much lower speeds, at positive driven pump is desirable. An example of the latter situation is disclosed in assignees patent to Mc- Cormick 2,410,514.

According to the present invention, the general system of the McCormick patent is improved by the utilization of a pump of the liquid-packing-ring type. In a pump of this character, a rotor or impeller revolves in an eccentric casing partly filled with liquid, which liquid approaches and recedes from the hub of the impeller and therefore acts as a liquid piston displacing the air in the spaces between the vanes of the impeller. The advantage of using the liquid-packing-ring type of pump in the crankcase ventilating system is that it avoids the disadvantages of using other types of pumps, because these pumps operate under adverse conditions of corrosion and a pump of the type referred to here minimizes the effects of such corrosion as well as providing an economical design with a minimum number of moving parts. A further advantage of the present arrangement is that the liquid-packingring is oil metered to the pump from an oil-containing part of the engine, preferably the crankcase. As the pump operates, the inside diameter of the liquid annulus or ring decreases as oil is fed in until it coincides with the outer edges of the inlet and outlet ports. Because the liquid is oil from the crankcase, additional oil added beyond that necessary to form the ring can escape through the exhaust port and will be returned to the crankcase. In some circumstances it may be desirable to avoid adding oil to the air inlet and for this purpose the air inlet can be made closer to the center of the chamber so that the inside diameter of the oil annulus is not coincident with the port.

The foregoing and other important objects and desirable features inherent in and encompassed by the invention will become apparent as a preferred embodiment of the invention is disclosed in detail in the ensuing specification and accompanying sheet of drawings, the two figures of which will be described immediately below.

Fig. l is a schematic view, partly in section and with parts broken away, illustrating the overall arrangement.

Fig. 2 is a section through the pump as seen on the line 22 of Fig. 1.

The schematic representation of the engine, designated generally by the letter E, includes a combustion chamber 10, a crankcase 12 and a housing portion 14 (Fig. 2) including an output shaft 16 which is utilized to drive an impeller shaft '18 for an impeller 20 of a pump P. A representative type of drive is disclosed in the above identified McCormick patent;

The pump P comprises a pump housing 22 within which the impeller is eccentrically located for rotation in the direction of the arrow 24. One wall of the pump housing is closed and the other has a pair of ports, one constituting an air inlet port 26 and the other comprising an air outlet port 28.

The vehicle or other arrangement in which the engine E and pump P are used may include an air cleaner A having its outlet side connected by an air conduit 30 with the combustion chamber portion 10 of the engine. The air inlet port 26 of the pump is connected by an air duct means 32 to the discharge side of the air cleaner A, in the present case the connection being effected by a T 34. The air outlet port 28 of the pump is connected by air duct means 36 to the crankcase 12, the duct means 36 entering the crankcase at 38, as shown in the broken away portion of Fig. 1. The entry portion 38 of the duct means 36 is well above the oil level L of a quantity of lubricating oil conventionally carried in the lower or sump portion of the crankcase, which sump here represents one form of liquidor oil-containing part for the engine. In its broader aspects, the invention contemplates the use of other liquidor oil-containing parts of the engine. The ventilating air pumped into the crankcase 12 via the pump P and air duct means 36 escapes from the crankcase via a discharge duct 40; although, it is conventional to utilize the discharged air for other purposes, as in combustion (see the above identified McCormick patent, for example). However, these uses of the air are immaterial here.

The pump P is of the liquid-packing-r-ing type, in which a ring or annulus of liquid (here oil) is introduced into the pump chamber and serves as liquid piston means for effecting the transfer of air from the air inlet 26 to the air outlet 28 as the impeller 20 rotates in the direction of the arrow 24 as previously described. Thus, clean air taken in from the air cleaner via the T at 34 is pumped across the pump to the duct means 36 and thence into the crankcase 12 via 38. According to the present invention, the liquid packing ring is, as shown in Fig. 1, an oil annulus confined at 42 by the inner periphery of the pump chamber 22 and having an inside diameter at 44. The annulus oil is supplied from the crankcase 12 by oil duct means 46 leading and being connected to an axial passage 48 in the impeller 20, which passage is supplemented by a radial passage 50 so that the oil entering at 48 escapes into the chamber to form the annulus 42-44 when the impeller rotates. The oil or other liquid supply may be regulated or metered, as by a needle valve 52.

As shown in Fig. 1, the inside diameter 44 of the ring or annulus of liquid lies just short of the air outlet port 28. In the event that additional oil is supplied, it may escape through the air duct means 36 and will thus be returned to the crankcase. In cases in which it is undesirable to permit escape of oil from the oil annulus 4244 into the air inlet line 32, the marginal edge of the port 26 may be placed closer to the center of the impeller, as compared the marginal edge portions 54 and 56 of the ports 26 and 28, respectively. Thus, excess oil in the ring will flow out through the outlet 28 before it will enter the inlet 26. I

The objects and advantages of the present arrangement have been covered above and need not be repeated.

1 3 Many advantages and features not categorically enumerated will undoubtedly occur to those versed, inthe art, as will minor modifications and alterations in the preferred embodiment of the invention disclosed, all of which may be achieved without departing from the .spirit and scope of the invention. t

What is claimed is:

1. In combination with an internal-combustion engine having a crankcase and including a lubricant-containing part, a pump of the liquid-packing-ring type-having a casing including a cylindrical wall and radial wall means forming a cylindrical chamber adapted .to be partly filled with lubricant, said pump further having an impeller journaled eccentrically in the chamber and including hub and radial vanes, said impeller being rotatable to generate centrifugal force which causes the lubricant in the casing to form a sealing and pumping annulus confined by the cylindrical wall of the casing, said radial wall means including an air inlet and an air outlet encircled by said annulus and said annulus, upon rotation of the impeller, :acting to relatively approach and recede from the impeller hub and to displace air from between the im peller vanes out through the air outlet, air duct means connecting said air outlet to and for supplying ventilating air to the crankcase, a lubricant inlet in the pump casing leading to said chamber, and lubricant duct means connecting the lubricant-containing part of the engine to said lubricant inlet for supplying lubricant to said chamber for use in said sealing and pumping annulus.

2. The invention defined in claim 1, in which: the liquid inlet to the chamber includes passage means in the impeller.

3. The invention defined in claim 1, in which: the air inlet in the casing is closer to the center of the chamber than the air outlet so that excess lubricant in said annulus tends to escape through the air outlet before it enters the air inlet.

Schittke Aug. 16, 1932 Witchger Oct. 11, 1949 

